By Kurtis Archer | 2026-01-26

Japan issued its first Space Domain Defense Guidelines in mid-2025 as it moved to increase its security, seeking to enhance its capabilities in the space domain while encouraging cooperation with private companies and allies.

Key objectives include deploying satellite constellations for potential-battlefield monitoring in real-time, working with partners to develop defensive satellite technologies, and strengthening space domain awareness to detect threats.

The guidelines, which include advancing space technologies to disrupt interference from adversaries, demonstrate the rapid evolution of Japan's approach to the space domain.

For close to 40 years, Japan had refrained from using space for national security purposes, in line with a 1969 parliamentary resolution limiting space development to "exclusively peaceful purposes."

Since the passage of the Basic Space Law of 2008, however, Japan's Ministry of Defense and Self-Defense Forces have begun to develop and use space systems.

Japan’s 2018 National Defense Program Guidelines called for the establishment of a "Multi-Domain Defense Force," and encouraged advancing technologies in space, cyber and electromagnetic warfare.

As a sign of the growing importance of space in Japan’s defense strategy, the Japan Air Self-Defense Force will be renamed the Japan Air and Space Self-Defense Force sometime in 2026 or 2027.

"Japan will build a mutually complementary structure with our Ally [the United States] and like-minded countries in terms of further strengthening capabilities and operational cooperation, while enhancing its autonomous defense capabilities in the space domain," the guidelines state.

Japan is working with the United States on satellite technologies, missile tracking systems, and lunar exploration. It is designing a lunar rover for NASA's Artemis program, and plans to send a Japanese astronaut to the moon.

In December 2024, US Space Force (USSF) established an operational unit in Japan as a response to growing tensions in the Indo-Pacific.

"Moving forward, promoting investment in the bilateral space partnership will assume even greater importance," Sean Wilson of the Center for Strategic and International Studies (CSIS) wrote in an April 9, 2025 analysis.

"Investment and partnership in cutting-edge space startups in both countries can enhance and expand the combined allied industrial base to the strategic benefit of both nations."

Chinese space aggression

Former Japanese Defense Minister Gen Nakatani cited satellite jamming and other adversarial space technologies from China and Russia as growing threats that necessitate the guidelines.

"Some countries are stepping up the development of technologies to interfere with and neutralize the satellites of other countries to secure their own military superiority, leading to the development of space as a warfighting domain and increasing threats and risks in outer space," according to Tokyo.

These technologies include Chinese and Russian "satellite killers" -- spacecraft that advance within range of target satellites and use robotic limbs or electromagnetic waves to disrupt their operations, per The Japan News.

Japan is developing a "bodyguard satellite" to protect against such attacks, with a prototype set to test its maneuvering capabilities in orbit by the end of 2029.

USSF has spoken about Chinese satellite activity it observed in March 2025.

"With our commercial assets, we have observed five different objects in space maneuvering in and out around each other in synchronicity and in control," then-USSF vice chief of space operations Gen. Michael Guetlein said.

"That's what we call 'dogfighting' in space,” Guetlein advised. "They are practicing tactics, techniques, and procedures to do on orbit space operations from one satellite to another."

China maintains it is simply testing in-orbit satellite refueling technologies.

Strained relationship

Relations between Japan and China have suffered since Japanese prime minister Sanae Takaichi indicated in November that the country's military would assist Taiwan, should China invade the self-governing democracy.

China responded by telling travelers to avoid Japan, among other measures.

Japan then accused China of aiming military radar at its fighter jets, the New York Times reported December 7.

"This radar lock-on incident constitutes a dangerous act that exceeds the scope necessary for the safe flight of aircraft," Japan’s defense minister Shinjiro Koizumi told an emergency news conference shortly after the incident.

"We view the occurrence of such an incident with utmost regret, and we have lodged a strong protest with the Chinese side while making a stern demand for measures to prevent any recurrence."

Chinese officials dismissed the accusation, and accused Japan of threatening space security by encouraging aggression, Global Times reported in December.

In mid-January, the Japanese foreign ministry confirmed that China is moving to build a new structure on the Chinese side of the median line between the two countries in the East China Sea, according to the Japan Times.

"It is extremely regrettable that China is advancing unilateral development in the East China Sea, while the exclusive economic zone and the continental shelf in the East China Sea have not yet been delimited," the ministry said.